H. L. Yim and S. H. Lee and S. K. Yoo and J. J. Kim, A Zero-Cost Collar Option Applied to Materials Procurement Contracts to Reduce Price Fluctuation Risks in Construction. journal = {International Journal of Economics and Management Engineering}, [online]. World Academy of Science, Engineering and Technology. December 2011, vol. 60(12). 1769 - 1774 [viewed 20 April 2024]. Available from: https://publications.waset.org/pdf/2482.